Biology subjects

Veesler, D.

Publications and source records attributed to Veesler, D..

At least 19 recordsLinked to original sources

bioRxiv2026

Structure and antigenicity of the 2026 Bundibugyo virus glycoprotein

An outbreak of ebolavirus disease caused by a new zoonotic spillover of Bundibugyo virus (BDBV) is currently spreading at an unprecedented pace in the Democratic Republic of the Congo and Uganda. The outbreak has resulted in 7,733 cases with a case-fatality ratio of 48%, yet no BDBV-specific vaccines or therapeutics are available. The ebolavirus glycoprotein (GP) promotes viral entry and is the target of neutralizing antibodies and vaccine development. Here, we engineered a soluble, prefusion-stabilized GP trimer from a contemporary BDBV isolate and determined its cryo-electron microscopy structure bound to the broadly neutralizing antibody EBOV-515. It reveals the molecular basis for EBOV-515 cross-reactivity and suggests that the antibody inhibits viral entry by interfering with NPC1 engagement in addition to trapping GP in the prefusion conformation and hindering glycan cap cleavage. Mapping lineage-defining substitutions identified changes in GP1 and GP2, including R506S within an antigenic site targeted by multiple broadly neutralizing antibodies recognizing the fusion loop. Nevertheless, we found that several glycan cap-, GP base-, and HR2-directed antibodies cross-reacted and neutralized BDBV DRC/2026 GP pseudovirus with potency comparable or greater to that observed against earlier BDBV isolates and the Zaire ebolavirus Makona/2024 isolate. These findings define the antigenic properties of contemporary BDBV GP and delineate conserved epitopes as ideal targets for antibody therapeutics and for the development of pan-ebolavirus vaccines.

biochemistry↗

bioRxiv2026

Computational design of potent, broadly neutralizing anti-Nipah virus and Hendra virus miniproteins

The prototype members of the genus Henipavirus, Nipah virus (NiV) and Hendra virus (HeV), cause recurrent zoonotic spillovers with case fatality rates ranging from 40-90% in humans. Currently, there are no approved vaccines or therapeutics for use in humans. Neutralizing antibodies targeting the NiV/HeV F- or G-glycoproteins protect animals from lethal challenge and are a main correlate of protection. However, antibody-based formulations are expensive, typically requiring hospital admission for administration and cold-chain for storage and transportation. To address the lack of shelf-stable clinical countermeasures, we computationally designed thermostable miniproteins that cross-react with subnanomolar affinities with both NiV and HeV F and G glycoproteins and inhibit viral entry in vitro with potencies comparable to lead antibodies. Oligomerized forms of these miniproteins have enhanced potency relative to their monomeric building blocks and increase the barrier for emergence of escape mutants, establishing them as promising preclinical candidates against these deadly viruses.

bioengineering↗

bioRxiv2026

Pan-neutralization of parainfluenza viruses by a hemagglutinin-neuraminidase antibody

Human parainfluenza viruses (HPIVs) can cause severe respiratory illnesses, such as croup, bronchiolitis, and pneumonia, particularly in children, the elderly and immunocompromised individuals. No vaccines or specific therapeutics are available for use in humans. Here, we report the discovery of a human monoclonal antibody designated PVA269 that broadly and potently neutralizes all four HPIV subtypes, PIV5, and Sendai virus by targeting the hemagglutinin-neuraminidase (HN) glycoprotein. We show that PVA269 inhibits neuraminidase activity and hemagglutination of erythrocytes through insertion of a long heavy chain complementary-determining region 3 in the enzyme active site. We reveal that the antibody markedly remodels its interactions to accommodate distinct viral features across HPIV subtypes, such as HPIV2 N-linked glycans. These results define the molecular basis for the unique PVA269 pan-neutralizing activity of human and animal viruses spanning two genera. PVA269 provides potent prophylactic activity against HPIV3 replication in the upper and lower airways of the clinically predictive cotton rat model, thus supporting translation of its protective efficacy to humans. These data establish PVA269 as a best-in-class monoclonal antibody and a promising clinical candidate to prevent HPIV infection, transmission, and disease in vulnerable populations.

immunology↗

bioRxiv2026

Mutations to the HCoV-229E spike have counterbalancing effects on serum antibody neutralization and receptor binding

Human coronavirus 229E (HCoV-229E) is an endemic pathogen that causes repeated "common-cold" infections throughout life. Like other coronaviruses, it accumulates spike mutations that erode antibody immunity and enable reinfection. Here, we use pseudovirus deep mutational scanning to measure how mutations to the HCoV-229E spike affect its cell entry function, binding to its human APN receptor, and neutralization by human sera with a range of sensitivities to erosion by viral evolution. We find that both receptor binding and serum neutralization are affected by mutations across spike, including many that modulate these properties by affecting the balance of up versus down conformations of the spike receptor-binding domain (RBD). In particular, some mutations increase both receptor binding and serum neutralization by shifting the RBD to a more up conformation, suggesting that the HCoV-229E spike has evolved to shield key RBD neutralizing epitopes at the cost of less efficient receptor binding.

microbiology↗

bioRxiv2025

Repeated COVID-19 vaccine boosters elicit variant-specific memory B cells in humans

The first exposure to a pathogen or an antigen profoundly impacts immune responses upon subsequent encounter with related pathogens. This immune imprinting explains that infection or vaccination with currently circulating SARS-CoV-2 variants primarily recalls cross-reactive memory B cells and antibodies induced by prior Wu spike (S) glycoprotein exposure rather than priming de novo responses. The magnitude and persistence of immune imprinting in mRNA vaccinated populations and the prospect to overcome it are not understood. To understand the impact of immune imprinting, we investigated memory B cell and plasma antibody responses after administration of multiple doses of XBB.1.5 and JN.1/KP.2 updated COVID-19 vaccine boosters. We found that administration of the JN.1/KP.2 booster elicited broadly neutralizing antibody responses against recently circulating SARS-CoV-2 variants that were accounted for by recall of Wu S-induced immunity. We detected an increased fraction of serum antibodies and particularly memory B cells recognizing XBB.1.5 S and KP.2 S, but not Wu S, relative to individuals who received a single XBB.1.5 booster a year prior. These findings suggest that repeated exposures to antigenically divergent S trimers contribute to progressively overcoming immune imprinting and support vaccine updates and innovation to provide continued protection against COVID-19. In briefImmune imprinting due to repeated SARS-CoV-2 Wuhan-Hu-1 spike exposures is widely observed in humans. Tortorici et al. show that the humoral immune response is dominated by recall of pre-existing Wu S-induced serum antibodies and memory B cells after administration of multiple XBB.1.5 and JN.1/KP.2 COVID-19 vaccine boosters. However, the detection of an appreciable fraction of serum antibodies and particularly memory B cells binding the updated vaccine antigens, but not Wu, suggests a path towards overcoming immune imprinting HighlightsO_LIXBB.1.5, JN.1 and KP.2 S COVID-19 vaccine boosters elicit neutralizing antibodies against current variants. C_LIO_LISerum neutralizing activity against circulating variants elicited after multiple doses of updated COVID-19 vaccine boosters derive from recall of Wu S-elicited antibodies. C_LIO_LINon-neutralizing antibodies specific for the updated spike antigens were detected after multiple, updated COVID-19 boosters. C_LI

immunology↗

bioRxiv2025

Functional and antigenic constraints on the Nipah virus fusion protein

Nipah virus is a highly pathogenic virus in the family Paramyxoviridae that utilizes two distinct surface glycoproteins to infect cells. The receptor-binding protein (RBP) binds host receptors whereas the fusion protein (F) merges viral and host membranes. Here, we use non-replicative pseudoviruses to safely measure the effects of all F single amino-acid residue mutations on its cell entry function and neutralization by monoclonal antibodies. We compare mutational tolerance in F with previous experimental measurements for RBP and show that F is much more functionally constrained than the RBP. We also identify mutationally intolerant sites on the F trimer surface and core that are critical for proper function, and describe mutations that are candidates for stabilizing F in the prefusion conformation for vaccine design. We quantify how F mutations affect neutralization by six monoclonal antibodies, and show that the magnitude of mutational effects on neutralization varies among antibodies. Our measurements of mutational effects on Nipah virus F predict the ability of the antibodies to neutralize the related Hendra virus. Overall, our work defines the functional and antigenic constraints on the F protein from an important zoonotic virus. ImportanceNipah virus sporadically spills over into humans, where it is often fatal. The Nipah fusion (F) protein is necessary for infection, and is a target for vaccines and antibody therapies. To better understand the constraints on this protein, we experimentally measured how [~]8,500 single amino-acid mutations to F affected its function using pseudoviruses that enable the safe study of protein mutants without the generation of actual replicative virus. We examined the effects of these mutations in the context of structural data and publicly available Nipah virus sequences to characterize the constraints that shape F protein evolution. This work has implications for understanding paramyxovirus fusion proteins, and informs the development of vaccines and monoclonal antibody therapies.

microbiology↗

bioRxiv2025

Potent neutralization of Marburg virus by a vaccine-elicited monoclonal antibody

Marburg virus (MARV) is a filovirus that causes a severe and often lethal hemorrhagic fever. Despite the increasing frequency of MARV outbreaks, no vaccines or therapeutics are licensed for use in humans. Here, we designed mutations that improve the expression and thermostability of the prefusion MARV glycoprotein (GP) ectodomain trimer, which is the sole target of neutralizing antibodies and vaccines in development. We discovered a fully human monoclonal antibody, MARV16, that broadly neutralizes all MARV isolates as well as Ravn virus and Dehong virus with 40 to 100-fold increased potency relative to previously described antibodies. We determined a cryo-electron microscopy structure of MARV16-bound MARV GP showing that MARV16 recognizes a prefusion-specific epitope spanning GP1 and GP2, blocking receptor binding and preventing conformational changes required for viral entry. We further reveal the architecture of the MARV GP glycan cap, which shields the receptor binding site (RBS), underscoring architectural similarities with distantly related filovirus GPs. MARV16 and previously identified RBS-directed antibodies can bind MARV GP simultaneously, paving the way for a MARV therapeutic antibody cocktail. MARV GP stabilization along with the discovery of a potent neutralizing antibody will advance treatment and prevention options for MARV.

immunology↗

bioRxiv2025

Phylogeny-driven design of broadly protective sarbecovirus receptor-binding domain nanoparticle vaccines

Vaccines against emerging SARS-CoV-2 variants and sarbecoviruses with pandemic potential must elicit a robust humoral immune response in a population imprinted with the SARS-CoV-2 spike (S) protein. Here, we designed protein nanoparticle (NP) vaccines co-displaying the SARS-CoV-2 BA.5, SARS-CoV-1, and BtKY72 receptor-binding domains (RBDs) with or without the Wuhan-Hu-1 (Wu) RBD. We show that these vaccines elicit cross-reactive and broadly neutralizing plasma antibody responses against SARS-CoV-2 variants and sarbecoviruses in naive and pre-immune animals. Immunization with multivalent RBD-NPs overcomes immune imprinting and elicits neutralizing antibodies and memory B cells specific for the BA.5, SARS-CoV-1, and BtKY72 RBDs in mRNA-1273-vaccinated non-human primates. Multivalent RBD-NPs outperform a monovalent Wu RBD-NP vaccine by providing superior protection in mice and non-human primates challenged with the vaccine-mismatched SARS-CoV-2 XBB.1.5 or the pre-emergent RsSHC014. These data support the use of multivalent RBD-NP vaccines for SARS-CoV-2 variants and sarbecoviruses in naive and pre-immune populations.

immunology↗

bioRxiv2025

Recognition of unique cell surface glycopolymers by diversified lectin domains specifies umbrella toxin targeting

The bacterial cell envelope provides structural integrity and is an essential conduit through which the organism interacts with its environment. However, the molecular structures of its constituents can also be exploited as receptors, permitting threats such as toxins and phage access to the cell. We previously demonstrated that Streptomyces coelicolor secretes an umbrella toxin particle that acts in a highly selective manner to inhibit the hyphal growth of competing Streptomyces strains. Here, we identify the receptor of umbrella toxins as teichuronic acid (TUA) oligosaccharides anchored to the cell surface through linkage to wall teichoic acids (WTA). We show that the carbohydrate portion of this previously undescribed hybrid TUA-WTA molecule is variable across species and that targeting specificity derives from its selective recognition by diversified lectin domains associated with umbrella particles. A cryo-EM structure of a lectin-TUA complex reveals the molecular basis for umbrella toxin cell targeting and, in conjunction with bioinformatic analyses, provides insights into a molecular arms race that we posit drives diversification of umbrella particles and the chemical composition of Streptomyces cell envelopes.

microbiology↗

bioRxiv2025

ACE2 utilization of HKU25 clade MERS-related coronaviruses with broad geographic distribution

Dipeptidyl peptidase-4 (DPP4) is a well-established receptor for several MERS-related coronaviruses (MERSr-CoVs) isolated from humans, camels, pangolins, and bats (1-6). However, the receptor usage of many genetically diverse bat MERSr-CoVs with broad geographical distributions remains poorly understood. Recent studies have identified angiotensin-converting enzyme 2 (ACE2) as an entry receptor for multiple merbecovirus clades. Here, using viral antigen and pseudovirus-based functional assays, we demonstrate that several bat merbecoviruses from the HKU25 clade previously thought to utilize DPP4 (7), employ ACE2 as their functional receptor. Cryo-electron microscopy analysis revealed that HsItaly2011 and VsCoV-a7 recognize ACE2 with a binding mode sharing similarity with that of HKU5 but involving remodeled interfaces and distinct ortholog selectivity, suggesting a common evolutionary origin of ACE2 utilization for these two clades of viruses. EjCoV-3, a strain closely related to the DPP4-using MERSr-CoV BtCoV-422, exhibited relatively broad ACE2 ortholog tropism and could utilize human ACE2 albeit suboptimally. Despite differences in entry mechanisms and spike proteolytic activation compared to MERS-CoV, these viruses remain sensitive to several broadly neutralizing antibodies and entry inhibitors. These findings redefine our understanding of the evolution of receptor usage among MERSr-CoVs and highlight the versatility of ACE2 as a functional receptor for diverse coronaviruses. SignificanceRecent studies unexpectedly revealed that several merbecoviruses convergently evolved ACE2 receptor usage with distinct binding modes across three continents, challenging the dogma that DPP4 is their primary receptor. Here, we demonstrate that HKU25 clade MERS-related coronaviruses broadly distributed across Eurasia utilize ACE2 as host receptor through a binding mode shared with HKU5, challenging prior findings. These findings reveal a prevalence of ACE2 usage in diverse MERS-related coronaviruses in bats and show that EjCoV-3 is preadapted to use human ACE2, suggesting a potential for spillover. Our data provide a blueprint of host receptor barrier determinants which will facilitate global surveillance and development of countermeasures against these poorly characterized merbecoviruses.

microbiology↗

bioRxiv2025

SARS-CoV-2 nsp1 mediates broad inhibition of translation in mammals

SARS-CoV-2 nonstructural protein 1 (nsp1) promotes innate immune evasion by inhibiting host translation in human cells. However, the role of nsp1 in other host species remains elusive, especially in bats which are natural reservoirs of sarbecoviruses and possess a markedly different innate immune system than humans. Here, we reveal that SARS-CoV-2 nsp1 potently inhibits translation in bat cells from Rhinolophus lepidus, belonging to the same genus as known sarbecovirus reservoirs hosts. We determined a cryo-electron microscopy structure of SARS-CoV-2 nsp1 bound to the Rhinolophus lepidus 40S ribosome and show that it blocks the mRNA entry channel via targeting a highly conserved site among mammals. Accordingly, we found that nsp1 blocked protein translation in mammalian cell lines from several species, underscoring its broadly inhibitory activity and conserved role in numerous SARS-CoV-2 hosts. Our findings illuminate the arms race between coronaviruses and mammalian host immunity (including bats), providing a foundation for understanding the determinants of viral maintenance in bat hosts and spillovers.

biochemistry↗

bioRxiv2024

Designed miniproteins potently inhibit and protect against MERS-CoV

Middle-East respiratory syndrome coronavirus (MERS-CoV) is a zoonotic pathogen with 36% case-fatality rate in humans. No vaccines or specific therapeutics are currently approved to use in humans or the camel host reservoir. Here, we computationally designed monomeric and homo-oligomeric miniproteins binding with high affinity to the MERS-CoV spike (S) glycoprotein, the main target of neutralizing antibodies and vaccine development. We show that these miniproteins broadly neutralize a panel of MERS-CoV S variants, spanning the known antigenic diversity of this pathogen, by targeting a conserved site in the receptor-binding domain (RBD). The miniproteins directly compete with binding of the DPP4 receptor to MERS-CoV S, thereby blocking viral attachment to the host entry receptor and subsequent membrane fusion. Intranasal administration of a lead miniprotein provides prophylactic protection against stringent MERS-CoV challenge in mice motivating future clinical development as a next-generation countermeasure against this virus with pandemic potential.

biochemistry↗

bioRxiv2024

Computational design of prefusion-stabilized Herpesvirus gB trimers

In the absence of effective vaccines, human-infecting members of the Herpesvirus family cause considerable morbidity and mortality worldwide. Herpesvirus infection relies on receptor engagement by a gH/gL glycoprotein complex which induces large-scale conformational changes of the gB glycoprotein to mediate fusion of the viral and host membranes and infection. The instability of all herpesvirus gBs have hindered biochemical and functional studies, thereby limiting our understanding of the infection mechanisms of these pathogens and preventing vaccine design. Here, we computationally stabilized and structurally characterized the Epstein-Barr virus prefusion gB ectodomain trimer, providing an atomic-level description of this key therapeutic target. We show that this stabilization strategy is broadly applicable to other herpesvirus gB trimers and identified conformational intermediates supporting a previously unanticipated mechanism of gB-mediated fusion. These findings provide a blueprint to develop vaccine candidates for these pathogens with major public health burden.

biochemistry↗

bioRxiv2024

Molecular basis of convergent evolution of ACE2 receptor utilization among HKU5 coronaviruses

DPP4 was considered a canonical receptor for merbecoviruses until the recent discovery of African bat-borne MERS-related coronaviruses using ACE2. The extent and diversity with which merbecoviruses engage ACE2 and their receptor species tropism remain unknown. Here, we reveal that HKU5 enters host cells utilizing Pipistrellus abramus (P.abr) and several non-bat mammalian ACE2s through a binding mode distinct from that of any other known ACE2-using coronaviruses. These results show that several merbecovirus clades independently evolved ACE2 utilization, which appears to be a broadly shared property among these pathogens, through an extraordinary diversity of ACE2 recognition modes. We show that MERS-CoV and HKU5 have markedly distinct antigenicity, due to extensive genetic divergence, and identified several HKU5 inhibitors, including two clinical compounds. Our findings profoundly alter our understanding of coronavirus evolution and pave the way for developing countermeasures against viruses poised for human emergence.

biochemistry↗

bioRxiv2024

Molecular basis of pathogenicity of the recently emerged FCoV-23 coronavirus

The ability of coronaviruses to recombine and cross species barriers affects human and animal health globally and is a pandemic threat. FCoV-23 is a recently emerged, highly pathogenic recombinant coronavirus responsible for a widespread outbreak of feline infectious peritonitis (FIP) likely linked to in-host viral evolution. Here, we report cryoEM structures of two FCoV-23 spike (S) isoforms explaining that the in-host loss of domain 0 observed in clinical samples enhances entry into cells and fusogenicity by facilitating protease access, leading to biotype switching and lethality. We show that FCoV-23 can use several aminopeptidase N (APN) orthologs as receptors and reveal the molecular determinants of receptor species tropism, including a glycan modulating human receptor utilization. We define antigenic relationships among alphacoronaviruses infecting humans and other mammalian species and identify a cross-reactive alphacoronavirus monoclonal antibody inhibiting FCoV-23 pseudovirus entry, paving the way for vaccine and therapeutic development targeting this highly pathogenic virus.

biochemistry↗

bioRxiv2024

A pan-variant miniprotein inhibitor protects against SARS-CoV-2 variants

The continued evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has compromised neutralizing antibody responses elicited by prior infection or vaccination and abolished the utility of most monoclonal antibody therapeutics. We previously described a computationally-designed, homotrimeric miniprotein inhibitor, designated TRI2-2, that protects mice against pre-Omicron SARS-CoV-2 variants. Here, we show that TRI2-2 exhibits pan neutralization of variants that evolved during the 4.5 years since the emergence of SARS-CoV-2 and protects mice against BQ.1.1, XBB.1.5 and BA.2.86 challenge when administered post-exposure by an intranasal route. The resistance of TRI2-2 to viral escape and its direct delivery to the upper airways rationalize a path toward clinical advancement.

biochemistry↗

bioRxiv2024

Computationally designed mRNA-launched protein nanoparticle vaccines

Both protein nanoparticle and mRNA vaccines were clinically de-risked during the COVID-19 pandemic1-6. These vaccine modalities have complementary strengths: antigen display on protein nanoparticles can enhance the magnitude, quality, and durability of antibody responses7-10, while mRNA vaccines can be rapidly manufactured11 and elicit antigen-specific CD4 and CD8 T cells12,13. Here we leverage a computationally designed icosahedral protein nanoparticle that was redesigned for optimal secretion from eukaryotic cells14 to develop an mRNA-launched nanoparticle vaccine for SARS-CoV-2. The nanoparticle, which displays 60 copies of a stabilized variant of the Wuhan-Hu-1 Spike receptor binding domain (RBD)15, formed monodisperse, antigenically intact assemblies upon secretion from transfected cells. An mRNA vaccine encoding the secreted RBD nanoparticle elicited 5- to 28-fold higher levels of neutralizing antibodies than an mRNA vaccine encoding membrane-anchored Spike, induced higher levels of CD8 T cells than the same immunogen when delivered as an adjuvanted protein nanoparticle, and protected mice from vaccine-matched and -mismatched SARS-CoV-2 challenge. Our data establish that delivering protein nanoparticle immunogens via mRNA vaccines can combine the benefits of each modality and, more broadly, highlight the utility of computational protein design in genetic immunization strategies.

immunology↗

bioRxiv2024

Functional and antigenic landscape of the Nipah virus receptor binding protein

Nipah virus recurrently spills over to humans, causing fatal infections. The viral receptor-binding protein (RBP or G) attaches to host receptors and is a major target of neutralizing antibodies. Here we use deep mutational scanning to measure how all amino-acid mutations to the RBP affect cell entry, receptor binding, and escape from neutralizing antibodies. We identify functionally constrained regions of the RBP, including sites involved in oligomerization, along with mutations that differentially modulate RBP binding to its two ephrin receptors. We map escape mutations for six anti-RBP antibodies, and find that few antigenic mutations are present in natural Nipah strains. Our findings offer insights into the potential for functional and antigenic evolution of the RBP that can inform the development of antibody therapies and vaccines.

evolutionary biology↗